Antennas unit having a radiating element arranged with a predetermined slant relative to a circuit board is proposed in Japanese Patent Application No. 2002-111377 and 2001-159672. In the antenna units, the radiating element is held by an antenna base or a bracket, namely, parts for holding the radiating element and complicated assembling work are required. Moreover, an array antenna is required for adjusting the maximum gain angle of directional patterns with a microstrip antenna. Thus, the antenna units are large in size.